The present invention relates to a novel dialkanoyloxybenzeylidene dialkanoate represented by the formula (I): ##STR2## wherein x.sup.1 and x.sup.2 represent respectively alkanoyloxy group, and a pharmaceutical composition in dosage unit form which comprises a dosage effective for the treatment of inflammatory disease of a compound represented by the formula (I) and a pharmaceutially acceptable carrier.
Dihydroxybenzaldehyde has recently attracted attention as an antitumour agent (refer to Japanese Patent Application Laying-Open No. 55-51018(1980)) and as an anti-inflammatory agent (refer to Japanese Patent Application Laying-Open No. 58-83619(1983)).
However, although dihydroxybenzaldehyde shows an excellent pharmacological activity in suppressing platelet aggregation and migration of leukocytes at a relatively low concentration in vitro, owing to the rapid metabolism thereof in the living body, it is necessary to administer a large amount thereof for a long time period for obtaining the effective effects of such pharmacological activity in vivo, and there are difficulties in administering thereof due to the stimulus action and the oxidizability of the aldehyde moiety thereof.
As a result of the present inventors' studies for developing a pharmaceutical agent which exhibits an effective pharmacological activity when administered to a living body even at a small dose rate while scarcely showing side effects, the present inventors have found the compound synthesized by the reaction, for instance, between a dihydroxybenzaldehyde and an alkanoic acid anhydride, which is represented by the formula (I): ##STR3## wherein x.sup.1 and x.sup.2 represent respectively alkanoyloxy group, and exhibits an effective pharmacological activity while scarcely showing side effects.
In the formula (I), the two x.sup.1 may occupy any of the following positions in the benzene ring thereof.
(2,3), (2,4), (2,5), (2,6), (3,4) and (3,5).
The alkyl group of the alkanoyloxy group represented by x.sup.1 and x.sup.2, respectively is a straight-chain or branched-chain alkyl group of from 1 to 18 carbon atoms, and x.sup.1 and x.sup.2 are independently represented by the formulae, ##STR4## respectively.